Mineral resources of the United States by United States. Bureau of Mines & Geological Survey (U.S.)

Author:United States. Bureau of Mines & Geological Survey (U.S.)
Language: eng
Format: epub
Tags: Mines and mineral resources, Mineral industries
Publisher: Washington : G.P.O.
Published: 1882-03-25T05:00:00+00:00

nace was of the same type as its predecessors, its capacity was still greater, and it differed in having three pairs of ore chambers placed side by side, and all heated by the same fireplace. Another modification was introduced in the middle pair of ore chambers. These were made with a 5-inch shelf slit, and were to be used for roasting granzita ; but it was found that the temperature best adapted for roasting tierras was not suited for granzita, and tierras only are now treated in all the chambers of this furnace.

Finally, in 1879, a new furnace, No. 2, with two ore chambers, having an 8-inch shelf slit, was introduced for treating the granzita ores, intermediate between granza and tierras. The granzita, it will be remembered, runs from 3J-inch down to 1^-inch diameter. In 1880, a second granzita furnace, No. 1, was built with two pairs of ore chambers. With the above imi)roved furnace plant, the economical treatment of fine and medium quicksilver ores may be said to be accomplished.

In the early history of the mine, according to most accounts, the condensation of quicksilver was very imperfectly effected. Prof. W. P. Blake, in a letter to Prof. J. D. Dana {a), dated February 14,1833, speaks of the loss of mercurial fumes escaping from the chimneys, and of ''the peculiar gray coating upon their tops." An article in the American Cyclopedia, some ten years later, speaks of the salivation of men and animals about the works, and "the deposit of mercurial soot upon the roofs around." During the last ten or twelve years, while improvements have been going on in furnace construction, constant attention has been given to the subject of condensation.

REDUCTION WORKS.

Situation and arrangement. —The beautiful spot occupied by the hacienda, or reduction works, is fauiiliar to many California travelers. It was chosen in the early history of New Almaden. The road leading to the mine leaves the San Jose valley, and, turning to the south, enters the canon of Los Alamitos creek. The handsome residence of the manager and the neat village of the officers and the workmen make a pleasing picture to the east of the well-shaded road. This latter is cooled by a running stream, a luxury all too rare in California summers. Just above the village the narrow caiion widens out to an area of a dozeu acres, giving barely room for the reduction works. The summit of Mine hill is a mile to the west of the hacienda in a direct line, aud 1,300 feet above it. A fine wagon road, 3 miles in leugth, and a shorter tramway, with self-acting inclines, serve to bring the ore from the mine to the works.

The ore tramway from the mine is situated at the foot of the tall bluffs behind the furnace, at a height of 60 feet above the furnace floor. From thence the ore is dumped into the ten chutes arranged

a American Jqumdl of Science, Vol. XVJI., p. 438,

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